<?php
/**
 * CPgsqlSchema class file.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @link http://www.yiiframework.com/
 * @copyright Copyright &copy; 2008-2011 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

/**
 * CPgsqlSchema is the class for retrieving metadata information from a PostgreSQL database.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @version $Id: CPgsqlSchema.php 3304 2011-06-23 14:53:50Z qiang.xue $
 * @package system.db.schema.pgsql
 * @since 1.0
 */
class CPgsqlSchema extends CDbSchema
{
    const DEFAULT_SCHEMA='public';

    /**
     * @var array the abstract column types mapped to physical column types.
     * @since 1.1.6
     */
    public $columnTypes=array(
        'pk' => 'serial NOT NULL PRIMARY KEY',
        'string' => 'character varying (255)',
        'text' => 'text',
        'integer' => 'integer',
        'float' => 'double precision',
        'decimal' => 'numeric',
        'datetime' => 'time',
        'timestamp' => 'timestamp',
        'time' => 'time',
        'date' => 'date',
        'binary' => 'bytea',
        'boolean' => 'boolean',
		'money' => 'decimal(19,4)',
    );

    private $_sequences=array();

    /**
     * Quotes a table name for use in a query.
     * A simple table name does not schema prefix.
     * @param string $name table name
     * @return string the properly quoted table name
     * @since 1.1.6
     */
    public function quoteSimpleTableName($name)
    {
        return '"'.$name.'"';
    }

    /**
     * Resets the sequence value of a table's primary key.
     * The sequence will be reset such that the primary key of the next new row inserted
     * will have the specified value or 1.
     * @param CDbTableSchema $table the table schema whose primary key sequence will be reset
     * @param mixed $value the value for the primary key of the next new row inserted. If this is not set,
     * the next new row's primary key will have a value 1.
     * @since 1.1
     */
    public function resetSequence($table,$value=null)
    {
        if($table->sequenceName!==null)
        {
            $seq='"'.$table->sequenceName.'"';
            if(strpos($seq,'.')!==false)
            $seq=str_replace('.','"."',$seq);
            if($value===null)
            $value="(SELECT COALESCE(MAX(\"{$table->primaryKey}\"),0) FROM {$table->rawName}) + 1";
            else
            $value=(int)$value;
            $this->getDbConnection()->createCommand("SELECT SETVAL('$seq', $value, false)")->execute();
        }
    }

    /**
     * Enables or disables integrity check.
     * @param boolean $check whether to turn on or off the integrity check.
     * @param string $schema the schema of the tables. Defaults to empty string, meaning the current or default schema.
     * @since 1.1
     */
    public function checkIntegrity($check=true,$schema='')
    {
        $enable=$check ? 'ENABLE' : 'DISABLE';
        $tableNames=$this->getTableNames($schema);
        $db=$this->getDbConnection();
        foreach($tableNames as $tableName)
        {
            $tableName='"'.$tableName.'"';
            if(strpos($tableName,'.')!==false)
            $tableName=str_replace('.','"."',$tableName);
            $db->createCommand("ALTER TABLE $tableName $enable TRIGGER ALL")->execute();
        }
    }

    /**
     * Loads the metadata for the specified table.
     * @param string $name table name
     * @return CDbTableSchema driver dependent table metadata.
     */
    protected function loadTable($name)
    {
        $table=new CPgsqlTableSchema;
        $this->resolveTableNames($table,$name);
        if(!$this->findColumns($table))
        return null;
        $this->findConstraints($table);

        if(is_string($table->primaryKey) && isset($this->_sequences[$table->rawName.'.'.$table->primaryKey]))
        $table->sequenceName=$this->_sequences[$table->rawName.'.'.$table->primaryKey];
        else if(is_array($table->primaryKey))
        {
            foreach($table->primaryKey as $pk)
            {
                if(isset($this->_sequences[$table->rawName.'.'.$pk]))
                {
                    $table->sequenceName=$this->_sequences[$table->rawName.'.'.$pk];
                    break;
                }
            }
        }

        return $table;
    }

    /**
     * Generates various kinds of table names.
     * @param CPgsqlTableSchema $table the table instance
     * @param string $name the unquoted table name
     */
    protected function resolveTableNames($table,$name)
    {
        $parts=explode('.',str_replace('"','',$name));
        if(isset($parts[1]))
        {
            $schemaName=$parts[0];
            $tableName=$parts[1];
        }
        else
        {
            $schemaName=self::DEFAULT_SCHEMA;
            $tableName=$parts[0];
        }

        $table->name=$tableName;
        $table->schemaName=$schemaName;
        if($schemaName===self::DEFAULT_SCHEMA)
        $table->rawName=$this->quoteTableName($tableName);
        else
        $table->rawName=$this->quoteTableName($schemaName).'.'.$this->quoteTableName($tableName);
    }

    /**
     * Collects the table column metadata.
     * @param CPgsqlTableSchema $table the table metadata
     * @return boolean whether the table exists in the database
     */
    protected function findColumns($table)
    {
        $sql=<<<EOD
SELECT a.attname, LOWER(format_type(a.atttypid, a.atttypmod)) AS type, d.adsrc, a.attnotnull, a.atthasdef
FROM pg_attribute a LEFT JOIN pg_attrdef d ON a.attrelid = d.adrelid AND a.attnum = d.adnum
WHERE a.attnum > 0 AND NOT a.attisdropped
	AND a.attrelid = (SELECT oid FROM pg_catalog.pg_class WHERE relname=:table
		AND relnamespace = (SELECT oid FROM pg_catalog.pg_namespace WHERE nspname = :schema))
ORDER BY a.attnum
EOD;
        $command=$this->getDbConnection()->createCommand($sql);
        $command->bindValue(':table',$table->name);
        $command->bindValue(':schema',$table->schemaName);

        if(($columns=$command->queryAll())===array())
        return false;

        foreach($columns as $column)
        {
            $c=$this->createColumn($column);
            $table->columns[$c->name]=$c;

            if(stripos($column['adsrc'],'nextval')===0 && preg_match('/nextval\([^\']*\'([^\']+)\'[^\)]*\)/i',$column['adsrc'],$matches))
            {
                if(strpos($matches[1],'.')!==false || $table->schemaName===self::DEFAULT_SCHEMA)
                $this->_sequences[$table->rawName.'.'.$c->name]=$matches[1];
                else
                $this->_sequences[$table->rawName.'.'.$c->name]=$table->schemaName.'.'.$matches[1];
                $c->autoIncrement=true;
            }
        }
        return true;
    }

    /**
     * Creates a table column.
     * @param array $column column metadata
     * @return CDbColumnSchema normalized column metadata
     */
    protected function createColumn($column)
    {
        $c=new CPgsqlColumnSchema;
        $c->name=$column['attname'];
        $c->rawName=$this->quoteColumnName($c->name);
        $c->allowNull=!$column['attnotnull'];
        $c->isPrimaryKey=false;
        $c->isForeignKey=false;

        $c->init($column['type'],$column['atthasdef'] ? $column['adsrc'] : null);

        return $c;
    }

    /**
     * Collects the primary and foreign key column details for the given table.
     * @param CPgsqlTableSchema $table the table metadata
     */
    protected function findConstraints($table)
    {
        $sql=<<<EOD
SELECT conname, consrc, contype, indkey FROM (
	SELECT
		conname,
		CASE WHEN contype='f' THEN
			pg_catalog.pg_get_constraintdef(oid)
		ELSE
			'CHECK (' || consrc || ')'
		END AS consrc,
		contype,
		conrelid AS relid,
		NULL AS indkey
	FROM
		pg_catalog.pg_constraint
	WHERE
		contype IN ('f', 'c')
	UNION ALL
	SELECT
		pc.relname,
		NULL,
		CASE WHEN indisprimary THEN
				'p'
		ELSE
				'u'
		END,
		pi.indrelid,
		indkey
	FROM
		pg_catalog.pg_class pc,
		pg_catalog.pg_index pi
	WHERE
		pc.oid=pi.indexrelid
		AND EXISTS (
			SELECT 1 FROM pg_catalog.pg_depend d JOIN pg_catalog.pg_constraint c
			ON (d.refclassid = c.tableoid AND d.refobjid = c.oid)
			WHERE d.classid = pc.tableoid AND d.objid = pc.oid AND d.deptype = 'i' AND c.contype IN ('u', 'p')
	)
) AS sub
WHERE relid = (SELECT oid FROM pg_catalog.pg_class WHERE relname=:table
	AND relnamespace = (SELECT oid FROM pg_catalog.pg_namespace
	WHERE nspname=:schema))
EOD;
        $command=$this->getDbConnection()->createCommand($sql);
        $command->bindValue(':table',$table->name);
        $command->bindValue(':schema',$table->schemaName);
        foreach($command->queryAll() as $row)
        {
            if($row['contype']==='p') // primary key
            $this->findPrimaryKey($table,$row['indkey']);
            else if($row['contype']==='f') // foreign key
            $this->findForeignKey($table,$row['consrc']);
        }
    }

    /**
     * Collects primary key information.
     * @param CPgsqlTableSchema $table the table metadata
     * @param string $indices pgsql primary key index list
     */
    protected function findPrimaryKey($table,$indices)
    {
        $indices=implode(', ',preg_split('/\s+/',$indices));
        $sql=<<<EOD
SELECT attnum, attname FROM pg_catalog.pg_attribute WHERE
	attrelid=(
		SELECT oid FROM pg_catalog.pg_class WHERE relname=:table AND relnamespace=(
			SELECT oid FROM pg_catalog.pg_namespace WHERE nspname=:schema
		)
	)
    AND attnum IN ({$indices})
EOD;
        $command=$this->getDbConnection()->createCommand($sql);
        $command->bindValue(':table',$table->name);
        $command->bindValue(':schema',$table->schemaName);
        foreach($command->queryAll() as $row)
        {
            $name=$row['attname'];
            if(isset($table->columns[$name]))
            {
                $table->columns[$name]->isPrimaryKey=true;
                if($table->primaryKey===null)
                $table->primaryKey=$name;
                else if(is_string($table->primaryKey))
                $table->primaryKey=array($table->primaryKey,$name);
                else
                $table->primaryKey[]=$name;
            }
        }
    }

    /**
     * Collects foreign key information.
     * @param CPgsqlTableSchema $table the table metadata
     * @param string $src pgsql foreign key definition
     */
    protected function findForeignKey($table,$src)
    {
        $matches=array();
        $brackets='\(([^\)]+)\)';
        $pattern="/FOREIGN\s+KEY\s+{$brackets}\s+REFERENCES\s+([^\(]+){$brackets}/i";
        if(preg_match($pattern,str_replace('"','',$src),$matches))
        {
            $keys=preg_split('/,\s+/', $matches[1]);
            $tableName=$matches[2];
            $fkeys=preg_split('/,\s+/', $matches[3]);
            foreach($keys as $i=>$key)
            {
                $table->foreignKeys[$key]=array($tableName,$fkeys[$i]);
                if(isset($table->columns[$key]))
                $table->columns[$key]->isForeignKey=true;
            }
        }
    }

    /**
     * Returns all table names in the database.
     * @param string $schema the schema of the tables. Defaults to empty string, meaning the current or default schema.
     * If not empty, the returned table names will be prefixed with the schema name.
     * @return array all table names in the database.
     * @since 1.0.2
     */
    protected function findTableNames($schema='')
    {
        if($schema==='')
        $schema=self::DEFAULT_SCHEMA;
        $sql=<<<EOD
SELECT table_name, table_schema FROM information_schema.tables
WHERE table_schema=:schema AND table_type='BASE TABLE'
EOD;
        $command=$this->getDbConnection()->createCommand($sql);
        $command->bindParam(':schema',$schema);
        $rows=$command->queryAll();
        $names=array();
        foreach($rows as $row)
        {
            if($schema===self::DEFAULT_SCHEMA)
            $names[]=$row['table_name'];
            else
            $names[]=$row['table_schema'].'.'.$row['table_name'];
        }
        return $names;
    }

    /**
     * Builds a SQL statement for renaming a DB table.
     * @param string $table the table to be renamed. The name will be properly quoted by the method.
     * @param string $newName the new table name. The name will be properly quoted by the method.
     * @return string the SQL statement for renaming a DB table.
     * @since 1.1.6
     */
    public function renameTable($table, $newName)
    {
        return 'ALTER TABLE ' . $this->quoteTableName($table) . ' RENAME TO ' . $this->quoteTableName($newName);
    }

    /**
     * Builds a SQL statement for adding a new DB column.
     * @param string $table the table that the new column will be added to. The table name will be properly quoted by the method.
     * @param string $column the name of the new column. The name will be properly quoted by the method.
     * @param string $type the column type. The {@link getColumnType} method will be invoked to convert abstract column type (if any)
     * into the physical one. Anything that is not recognized as abstract type will be kept in the generated SQL.
     * For example, 'string' will be turned into 'varchar(255)', while 'string not null' will become 'varchar(255) not null'.
     * @return string the SQL statement for adding a new column.
     * @since 1.1.6
     */
    public function addColumn($table, $column, $type)
    {
        $type=$this->getColumnType($type);
        $sql='ALTER TABLE ' . $this->quoteTableName($table)
        . ' ADD COLUMN ' . $this->quoteColumnName($column) . ' '
        . $this->getColumnType($type);
        return $sql;
    }

    /**
     * Builds a SQL statement for changing the definition of a column.
     * @param string $table the table whose column is to be changed. The table name will be properly quoted by the method.
     * @param string $column the name of the column to be changed. The name will be properly quoted by the method.
     * @param string $type the new column type. The {@link getColumnType} method will be invoked to convert abstract column type (if any)
     * into the physical one. Anything that is not recognized as abstract type will be kept in the generated SQL.
     * For example, 'string' will be turned into 'varchar(255)', while 'string not null' will become 'varchar(255) not null'.
     * @return string the SQL statement for changing the definition of a column.
     * @since 1.1.6
     */
    public function alterColumn($table, $column, $type)
    {
        $type=$this->getColumnType($type);
        $sql='ALTER TABLE ' . $this->quoteTableName($table) . ' ALTER COLUMN '
        . $this->quoteColumnName($column) . ' TYPE ' . $this->getColumnType($type);
        return $sql;
    }

    /**
     * Builds a SQL statement for dropping an index.
     * @param string $name the name of the index to be dropped. The name will be properly quoted by the method.
     * @param string $table the table whose index is to be dropped. The name will be properly quoted by the method.
     * @return string the SQL statement for dropping an index.
     * @since 1.1.6
     */
    public function dropIndex($name, $table)
    {
        return 'DROP INDEX '.$this->quoteTableName($name);
    }
}
